Standard Testing Procedure - Tensile Testing t5v5x

XYZ Section: Metallic materials

STANDARD TEST PROCEDURES MANUAL

Subject: Tensile Testing DOC. No. :

1) SCOPE: I.

This method prescribes a procedure for conducting the Tensile Test for metallic materials.

2) DEFINITION: a. Gauge Length is the portion of the test piece on which elongation shall be measured. b. Parallel Length (LC):Parallel portion of the reduced section of the test piece. c. Original Gauge length (Lo ): Gauge length before application of force.

d. e.

Final Gauge Length (Lf): Gauge length after rupture of the test piece. Percentage Elongation (ϵ): Increase in original gauze length (Lf – Lo) after fracture expressed as percentage of the original gauze length (Lo). Maximum Force (Fm): Greatest force which the test piece withstands during the test. Cross Sectional Area (So): Minimum original cross sectional area of test specimen. Stress (σ):At any moment during the test, force divided by the original cross sectional area (So) of the test piece. Tensile Strength (Rm): Maximum Force (Fm) divided by the original cross sectional area (So). Upper Yield Strength (Ys): Value of the stress at the moment when first decrease in force (F y) is

f. g. h. i. j.

observed.

3) APPARATUS USED: I. Universal Testing Machine (UTM). II. Vernier Calliper, Micrometer. 4) PROCEDURE: a) Thickness of the test specimen to be used for sheets & flats should be equal to or greater than 3mm and for wire, bars & sections of diameter or thickness greater than or equal to 4mm.

b) Dimensions of the test piece (Rectangular or Cylindrical) shall be as follows: LO

r

OR

W T

LC

D

Lt

Referenc Designation e Number Cross Sectional Area So LC LO Lt T/D W r

Parallel Length Original Gauze Length Minimum Total Length Thickness / Diameter Maximum Width Minimum Radius

Rectangular Test Piece

Cylindrical Test Piece

TXW L O + 2 √S o 5.65 √So LC + 80mm

Π (0.5D)2 LO + 2D 5.65 √So LC +80mm

T W:T : : 8:1 12mm

0.75 D but >4mm ----0.75 D

c) Calculate and note the original cross sectional area upto two decimal points in square millimetres. d)Calculate the original gauze length and round it off to the nearest multiple of 5mm. Each end of the gauze length shall be marked by means of fine marks or scribed lines only. Page 1 of 3

XYZ Section: Metallic materials

STANDARD TEST PROCEDURES MANUAL

Subject: Tensile Testing DOC. No. :

e) Select the suitable scale on Dial Gauze of UTM and mount the appropriate standard mass on the pendulum of UTM situated in the cabinet of control . Scale Combination of Standard mass 0 to 60 KN Pendulum without any attached mass 0 to 120 KN Smallest standard mass on pendulum 0 to 300KN Smallest + medium standard mass 0 to 600KN Smallest + Medium + Heaviest mass on Pendulum f) Switch on the machine by the on off switch given on control ensuring the release valve is open and Open / Close valve is at close position. g)Clamp the test piece firmly between the jaws of UTM u and DOWN switch. h) Ensure that graph and plotter are clamped and functioning properly. i) Close the RELEASE valve tightly and very slowly open the OPEN / CLOSE valve. j) Gradually rotate the OPEN / CLOSE valve slowly and at fixed rate in anticlockwise direction as load is brought in action without any jerk and respective load could be checked on the dial gauge. k) As soon as the test specimen fractures note down the maximum applied load and immediately close the OPEN / CLOSE valve and open the RELEASE valve. l) Unclamp the test fractured test specimen and measure the final gauze length by ing the fractured ends.

5) CALCULATION: a) Yield Strength (YS) :

Fy

So

N/ mm2

1) SO = Original cross-sectional area in mm2. 2) FY = Value of force at the yield point in Newton (could be obtained from graph) b) Tensile Strength (Rm) :

Fm

So

N/ mm2

1) Fm = Maximum force during test in Newton (Could be read from Dial Gauze or from Graph) Lf - Lo

Lo

X 100

%

c) Percentage Elongation (ϵ) : 1) Lf = Final Gauze Length in millimetre (obtained by ing fractured ends of test specimen) 2) Lo = Original Gauze Length

6) ADDED INFORMATION: I.

REFRENCES: IS: 1608 : 2005 ISO : 6892 : 1998 Page 2 of 3

XYZ Section: Metallic materials

STANDARD TEST PROCEDURES MANUAL

Subject: Tensile Testing DOC. No. :

II.

Prepared By:

GENERAL: a. Ensure that Universal Testing Machine, Vernier Callipers and Micrometer is regularly calibrated within prescribed time period. b. Test shall be carried out at ambient temperature 10⁰C to 35⁰C. c. Test piece shall be held in Jaws in such a way that the force is applied as axially as possible. d. When measuring the final gauze length special precaution shall be taken to ensure proper between the broken parts of the test piece. e. If the fracture point and the nearest gauze mark is less than the one third of the original gauze length and also the percent elongation is less than the specicified value the test shall be discarded and retested with a fresh test specimen. f. Original cross sectional area shall be calculated from measurements of the appropriate dimensions with an accuracy of ±0.5% and could also be calculated using mass of a known length and its density.

__DEVENDRA SINGH____ Sr. Engineer - Quality XYZ

Approved By:

_____________________ XYZ

Page 3 of 3